Since this sort of thing is what my career has been about (preventing such fires, not promoting them than you very much), I've been looking for clues. I think I found one. In the recent 10 million pound renovation, the
concrete (translation -- non-combustible) exterior was clad with decorative panels called Reynobond. As might be gathered from the name, these are a product of Reynolds Aluminum. From what I gather, they appear to be an insulated cladding panel with a thin aluminum skin bonded to a foam plastic insulating layer.
Problem: most plastic foams are highly combustible. There are some types that aren't, and the difference can be crucial. For example, in the Station Nightclub fire, it was discovered that the owners installed a non-treated (i.e. very flammable) eggcrate foam on the interior surfaces as sound control, when the building and fire codes required it to be a non-combustible type. But the non-treated type is cheaper.
Fast forward to the fire in London. Reynobond literature:
https://www.arconic.com/aap/north_america/catalog/pdf/brochures/reynobond_brochure.pdfReynobond is designed and tested to meet sfaety and environmental building codes around the world. It is available with either a polyethylene (PE) core or a fire-resistant (FR) core material, both of which provide the flatness and formability required for your most demanding applications.
Based on past experience, I'm willing to go out on a limb and predict that the verson with the FR core is more expensive, so the bean counters decided to use the PE core version. BAD decision.